Most epidemiological research on infant feeding has been static in conceptualization and focused narrowly on analysis of the extent and duration of breast feeding. Little insight into either dynamics of changes in infant-feeding patterns or their determinants has been provided. This study uses a unique longitudinal set of biomedical, dietary intake, industry marketing and socio- demographic information to address questions about feeding patterns and determinants. It is a supplemental proposal designed to address two tasks not funded in the original proposal. The first task, data base development and analysis of the full pattern of infant feeding, has been funded and is in process. Clustering techniques are being used to construct logical food categories to be used in describing the changing character of the milk and supplemental food components of infant diets over the first two years of life. The end product will be two-year feeding profiles for each child and a number of descriptive studies of infant-feeding behavior. The second task consists of two descriptive determinants studies. The first study will sort out the various ways that the infant food industry can have an impact on the feeding decisions of mothers. The second study will analyze the multitude of biomedical factors that can affect the infant's diet. These studies will provide important insights into the determinants of infant-feeding behavior and will be used to select a limited set of explanatory variables for use in task three. The third task will be a dynamic analysis of feeding pattern changes and the factors associated with them over time. Biomedical, socioeconomic, and community factors will be used to explain the choice of feeding pattern. Modeling and estimation techniques will be used which make full use of the longitudinal nature of the data set. This project analyzes data collected from a randomly selected sample of more than 2,600 Filipino mother-infant pairs, followed from the mothers' pregnancies through the first two years of the infants' lives.